1. Field of the Invention
This invention relates to a robot finger, especially a robot finger of a hollow bellows-like body which, upon introduction of a fluid pressure, e.g., gas under pressure, within the interior thereof can be deformed in only one direction towards a gripping pad disposed lengthwise along the length thereof so that the movement of the hollow body upon an increase in pressure resembles the movement of a human finger. This invention particularly relates to a robot finger which will respond to fluid pressures within the interior thereof by accommodating any reactive force which may act upon the finger. This invention is particularly directed to a robot finger having a gripping pad which is restrained from movement toward the hollow body by the use of a stiffening and/or support member so as to make the assembly resistant to forces upon which the robot finger may act.
2. Discussion of the Prior Art
Robot fingers have heretofore been proposed especially for use with automatons serving for the manipulation of parts. These robot fingers are often part of a robot hand which performs gripping functions. These gripping functions are provided by a robot finger and/or robot hand and serve to move materials and apparatus in accordance with pre-programmed instructions. Often, the robot fingers are responsive to fluid pressures arising within the fingers. The movements involved in grasping with a human hand can be simulated with a robot hand mechanically only, heretofore, by highly complex and troublesome mechanisms involving a large number of articulated parts.
On account of the articulations which are needed whose manufacture requires great precision, systems of this kind additionally require constant maintenance and are subjected to a great deal of wear. Furthermore, mechanical grippers as a rule are not sufficiently versatile as they have to be especially constructed to fit the geometry and dimensions of the material on which they are to act. Accordingly, a considerable expenditure of time is required for the conversion of the manipulating robots equipped in this manner so that they are adaptable to a different material to be manipulated.
The adaptability of the human hand to the geometry and measurements of the parts to be manipulated and especially the human hand's peculiar adaption of force to the kind of material being manipulated are goals which have not thus far been achieved in a satisfactory manner.
Thus, it has been discovered that gripping means which are intended to simulate the action of a human finger are not adequate. In U.S. Pat. No. 3,343,864 there is disclosed a gripping means in the nature of a robot finger. The gripping means according to this patent is, unfortunately, utterly flabby in the loading direction in the unpressurized state and is only slightly stiffened by the application of fluid pressure. As a result of this flabby construction, an excess pressure of more than 4.7 bars must be applied within the robot finger before the gripping means exercises any measurable force at all upon the object to be gripped. If one considers that the overpressure in a compressed-air network normally amounts to 5-6 bars, such gripping means cannot be used due to its inadequate holding power.
Therefore, it becomes desirable to provide an improved robot finger which did not require an excess amount of pressure therewithin which was not in a flabby condition and could act upon a material to be manipulated without the use of excess pressure. It became particularly desirable to provide such a robot finger which would manipulate objects through the use of fluidized pressure where the fluid pressure did not exceed about 6 bars. Particularly, it became desirable to provide a robot finger which could not be deformed away from the article to be gripped and which would provide a positively acting force against the object to be gripped upon the introduction of fluid pressure within the robot finger. These and other long-felt desiderata in the art are answered in accordance with the robot finger of this invention described below.